The Stress-System Model for Functional Somatic Symptoms

This chapter introduces the reader to the stress-system model for functional somatic symptoms through the personal journey of the first author. The stress-system model provides clinicians with a framework for thinking about the neurobiology of functional somatic symptoms and for explaining them to children and their families. The components of the brain-body stress system—the neurobiological systems that regulate body state—include the circadian clock, hypothalamic-pituitary-adrenal axis, autonomic nervous system, immune-inflammatory system, and brain stress systems that underpin salience detection, arousal, pain, and emotional states. All components of the stress system are interconnected and form part of a larger, integrated system that ensures effective energy regulation, promotes health and survival, and protects the individual from a broad range of threats. When the stress system—or one or more components of the stress system—is activated too much, too little, too long, or in aberrant ways, or when it fails to return to baseline function, then functional somatic symptoms may arise.